TENOSIQUE, Mexico -- For years, Mexico's most closely watched border was its northern one, which generations of Mexican migrants have crossed seeking employment and refuge in the United States.

But the sudden surge of children from Central America, many of them traveling alone, has cast scrutiny south, to the 600-mile border separating Mexico and Guatemala.

Now Mexico finds itself whipsawing between compassion and crackdown as it struggles with a migration crisis of its own. While the public is largely sympathetic to migrants and deeply critical of the United States' hard-line immigration policies, officials are under pressure from their neighbors to the north and south as they try to cope with the influx. As a result, they are taking measures that would have been unthinkable just a few years ago.

Mexico has quietly stepped up the pace of deportation of migrants, some of them unaccompanied children. It announced plans to stop people from boarding freight trains north and will open five new border control stations along routes favored by migrants.

"Never before has Mexico announced a state policy on the border, and now it has," said Interior Secretary Miguel Angel Osorio Chong. "It is absolute control of the southern border."

But at the same time, and the part that the Mexican government and President Enrique Pena Nieto emphasized in a speech at the border, Mexico and Guatemala plan a new guest worker program and temporary, three-day transit visa -- both free -- allowing access to four border states in an effort, the interior minister said, to have an "orderly flow."

The program might be extended to Hondurans and Salvadorans, he said, adding that controlling the process would make migration safer and outweigh any concern about attracting more people.

Although thousands of children, families and adults have made it to the United States, often with the help of a smuggler paying off law enforcement officers along the way, Mexican officials estimate that half of those who try do not, instead getting stranded in Mexico when they run out of money or are detained by immigration agents patrolling buses, checkpoints, hotels and places they transit.

Last year, Mexico deported 89,000 Central Americans, including 9,000 children, with the bulk of the returnees from Honduras, Guatemala and El Salvador, officials have said. In the fiscal year that ended last September, the United States sent back 106,420 from those countries.

So far this year, Mexico has detained 53 migrant children each day, mostly Central American, double the pace of the same period last year. It has deported more than 30,000 Central Americans this year, including more than 14,000 Hondurans, driven home on packed buses at least three times a week.

Francisco Alba, a migration scholar at the Colegio de Mexico in Mexico City, said the influx creates a conundrum: It is almost impossible to stop the flow, yet the country cannot support a large population of refugees.

"There is not really much the country can do about it," Alba said. "It cannot really stop these flows. Its tradition is to not have these tight controls and to have a relatively accommodating attitude toward migration, to a point."

But now Mexico plans to bolster its border security, including a plan to stop waves of people, some of them with babies and toddlers, from stowing away on a northbound freight train known as The Beast, because of rampant accidents and violent crime. Images of the train and the little done to stop it had appalled members of the U.S. Congress and human-rights advocates.

In a recent accident, a 2-year-old boy fell from the train and suffered the partial amputation of his leg while traveling with his mother from Honduras to reunite with her American father in Texas. The woman, a 23-year-old aspiring graphic artist, severely injured the arm she uses to draw.

"They will not be able to get on the train," Osorio Chong said of migrants, promising details of how they will be stopped in the coming days.

"They cannot use this train because their lives are at risk, and they don't have permission to be in the country."

Mexico is deporting migrants at a brisk clip as its shelters fill up with families and children who are broke, exhausted and now daunted by the long, often dangerous trek and spreading word that legal entry to the United States would be nearly impossible.

Advocates worry that migrants might be pushed to take more dangerous routes or pay larger bribes to immigration agents and the police, already a widespread practice.

"It is just going to make everything even more underground," said Ruben Figueroa, an activist who helps migrants at a shelter in Mexico.

A Section on 07/20/2014